Results of the recent application studies of laser-based techniques for conservation practice, carried out in the frames of
research and conservation projects are presented and discussed. The Gotland Sandstone Project covers laser cleaning,
spectroscopic techniques of the process monitoring and materials analysis. The post-processing effect is investigated by
means of LIBS, colorimetry, SEM and XEDS in order to answer questions regarding encrustation removal, discoloration
and alteration due to environmental pollution and laser interaction, respectively. The cleaning is monitored acoustically.
Slight differences in stone yellowing are revealed when applying laser in air or pure N2 environment which is ascribed to
material oxidation and partial combustion of surface remnants due to presence of O2 contributing to the final effect of
laser cleaning. Results of microscopic observation are supported by the presence of elements S, Al, Ca, and C which
prevail in crust. In case of restoration of the historical documents on paper the ablative cleaning and the nearly nondestructive
identification and composition analysis of surface layers such as contaminants, substrate and pigments are
performed. Spectra obtained by means of the LIPS technique for historical, originally contaminated and also artificially
soiled model samples reveal reach structures. The emission lines of Ca, Na, K, Al and Fe are ascribed to contaminants
because of intensities decreasing with prolonged surface irradiation during laser cleaning. Bands of Ti and Ba correspond
to white pigments (TiO2 and BaSO4) in the paper and are confirmed by the Raman spectra as well. For identification of
historical pigments the reference measurements on model substrates are performed, too.